using System;
using System.Collections.Immutable;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Reactive;
using System.Reactive.Linq;
using System.Text.RegularExpressions;
using Avalonia.Controls.Platform;
using DynamicData;
using DynamicData.Binding;
using ReactiveUI;
using Splat;
using StarsAssistant.Model;
using StarsAssistant.ViewModels;

namespace StarsAssistant.Services;

public class FleetManager : IEnableLogger, IDisposable
{
    protected Services.Game Game = Locator.Current.GetService<Services.Game>()!;

    /// <summary>
    /// SourceList for fleets read from the game files
    /// </summary> 
    private SourceList<Fleet> _fleets = new();

    /// <summary>
    /// Fleet data summarized by destination, will be chaned to _fleets
    /// </summary>
    private SourceCache<FleetSummary, string> _fleetSummaries = new(fs => fs.Destination);

    /// <summary>
    /// Public accessor to the continously updated fleet summaries.
    /// </summary>
    public IObservableCache<FleetSummary, string> FleetSummaries => _fleetSummaries.AsObservableCache();

    /// <summary>
    /// Disposal tracking
    /// </summary>
    private IDisposable _fleetSummariesSubscription;

    public FleetManager() 
    {
        CreateFleetSummariesLink();
    }

    [MemberNotNull(nameof(_fleetSummariesSubscription))]
    protected void CreateFleetSummariesLink()
    {
        _fleetSummariesSubscription = _fleets.Connect()
            .Filter(fleet => fleet.TrueDestination != "-- ")
            .GroupOn(fleet => fleet.TrueDestination)
            .Log(this, $"{DateTime.Now.ToLongTimeString()} fleetWatcher", grp => $"{grp.TotalChanges} detected")
            .Transform(group => new FleetSummary
                {   
                    Destination = group.GroupKey,
                    TotalIronium = group.List.Items.Sum(f => f.Ironium),
                    TotalBoranium = group.List.Items.Sum(f => f.Boranium),
                    TotalGermanium = group.List.Items.Sum(f => f.Germanium),
                    TotalColonists = group.List.Items.Sum(f => f.Colonists)
                })
            .AddKey(fs => fs.Destination)
            .Log(this, "FleetManager _fleetSummaries update", changes => 
                    $"{changes.Adds} adds, {changes.Updates} updates, {changes.Removes} removes"
                )
            .PopulateInto(_fleetSummaries)
        ;

        /*
        // Demo only
        var sourceCache = new SourceCache<FleetSummary, string>(fs => fs.Destination);
        var tmp = fleetSummaries
            .AddKey(fs => fs.Destination)
            .PopulateInto(sourceCache);
        
        _fleetSummaries
            .ObserveOn(RxApp.MainThreadScheduler)
            .Bind(out summaries)
            .DisposeMany()
            .Subscribe();

        d1 = summaries
            .Subscribe(Observer.Create<FleetSummary>(f => 
                {
                    this.Log().Debug($"FleetSummary observed: {f}");
                }
            ));

        d2 = _fleetSummaries
            .ObserveOn(RxApp.MainThreadScheduler)
            .Subscribe(x => 
            {
                var lst = x.ToList();
                foreach (var f in lst)
                {
                    this.Log().Debug($"Reason {f.Reason}, Type {f.Type}: {f.Item.Current}");
                }
            }
            );
        */
    }

    /// <summary>
    /// Load the fleet records from the database and push them into our source cache.
    /// If the data has been freshly imported, call PostProcessImportedData first.
    /// </summary>
    public void InitFromDatabase()
    {
        using var db = Locator.Current.GetService<StarsDatabase>()!;
        var allFleets = db.Fleet.ToList();
        _fleets.Edit(innerCache =>
            {
                innerCache.Clear();
                innerCache.Add(allFleets);
            }
        );
    }

    /// <summary>
    /// Helper to fill up missing data from the original import. Tries to deduce
    /// missing properties using heuristics.
    /// </summary> 
    public static void PostProcessImportedData()
    {
        using var db = Locator.Current.GetService<StarsDatabase>()!;

        // Check for all cases where we're targeting another fleet instead of
        // a planet. Update the DB accordingly.
        var playerFleets = from flt in db.Fleet
            where flt.OwnerFileId == Game.Player.PlayerFileId
            select flt;

        Regex shipPattern = new ($@"^{Regex.Escape(Game.Player.Name)} (?<ShipType>.+) #\d+$");

        foreach (Fleet flt in playerFleets)
        {
            if (flt.Destination != "-- ")
            {
                var trueDest = db.Fleet
                    .FirstOrDefault(f => f.FleetName == $"{Game.Player.Name} {flt.Destination}"
                        && f.Planet != String.Empty);
                flt.TrueDestination = trueDest?.Planet ?? flt.Destination;
            }
            else
            {
                flt.TrueDestination = "-- ";
            }
            
            Match m = shipPattern.Match(flt.FleetName);
            if (m.Success)
                flt.ShipTypeGuess = m.Groups[1].Value;

            db.Update(flt);            
        }

        db.SaveChanges();
    }

    /// <summary>
    /// Handle disposal of all subscriptions and dependencies.
    /// </summary>/
    protected virtual void Dispose(bool disposing)
    {
        if (disposing)
        {
            _fleetSummariesSubscription.Dispose();
            _fleetSummaries.Dispose();
            _fleets.Dispose();
        }
    }

    /// <summary>
    /// Boilerplate disposal
    /// </summary>
    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }
}